This application relates to the art of spacers and, more particularly, to spacers for spacing rigid conduit or the like from a surface to which the conduit is secured.
Known clamp back spacers for conduit include the type disclosed in U.S. Pat. No. 3,559,933 issued Feb. 2, 1971, to Castellani. In the Castellani spacer, there is a relatively large opening and slot for receiving a screw which secures the spacer to a surface. This would allow the spacer to move longitudinally in one direction relative to the screw so it is necessary to firmly hold the spacer in its desired position while the mounting screw is tightened. Two or more stacked Castellani spacers can shift transversely relative to one another because they are not locked together against movement and special care must be used to be sure the spacers do not rotate or shift transversely relative to one another during mounting.